Under peculiar system load conditions, the profiler thread
does not get enough CPU slices to perform the sampling.
Improve the interaction between worker and parent thread
by performing a large disc read, which is a better blend of
CPU and I/O bound work, than earlier versions.
This produces x10 more samples than the existing one,
in 10 iterations, as opposed to 1024.

Also capture worker error situations to improve debugging

Refs: nodejs#26401 (comment)